Johan s



J. S. FASTING.

ROTARY KILN.

APPUCATION FILED JULY 18. 1918.

Patented Aug. 19, 1919.

UNITED STATES" PATENT oF IcE,

30mm s. FASTING, OF FREDERIKSBERG, NEAR COPENHAGEN, DENMARK, ASSIG-NORT0 F. L. SMIDTH & 00., or NEW YORK, 1v. Y., A coRroRA'rIoN on NEWJERsEY.

ROTARY KEN.

Specification of Letters Patent.

Patented Aug. 19, 1919.

Application and July 1a, 1918. serial No. 245,522.

following is a specification, reference being had to the accompanyingdrawing, forming a part hereof.

This invention has for its object to increase the efficiency of rotarykilns in which the material to be burned, such as 'the raw materials ofPortland cement, is introduced at the feeding end of the kiln in theform of slurry. In accordance with the invention the feeding end of thekiln is provided with a series of helically arranged chains which aresecured to the inner wall of the kiln, with the inner end of each inadvance, circumferentially and in the direction of rotation of the kiln,of the outer end and, as-the kiln rotates, are alternately plunged intothe slurry and lifted out of the same, whereby some of the slurry istaken up by the chains and is caused to traverse'the cross sectionalarea of the kiln and the entire volume of the products of combustion andat the same time is caused to move inwardly in the kiln, that is, towardthe discharge end. Thereby the surface of the slurry exposed forevaporation is greatly increased, the absorption of heat. by' the slurryis promoted, the unconsumed particles of fuel are caught and returnedwith the slurry to a point in the kiln where their combustion may becompleted, and dust particles which would otherwise have to be caught ina dust chamber or would escape into the air, are caught by the slurryand are combined with it. The invention will be more fully describedhereinafter with reference to the accompanying drawing in which itisillustrated, and in which Figure 1 is a view in elevation of the rotarykiln to which the invention may be applied.

. Fig. 2 is a view in elevation of the inlet end of the kiln on alarger-scale.

Fig. 3 is a detail view'in cross section on astill larger scale lookingtoward the left in.

'the chains.

Fig. 6 is a diagrammatic View of a development of the inner wall of thekiln indicating the disposition of the cross chains.

As represented in Fig. 1, the kiln a may be of ordinary construction,being provided at ts inlet end with a suitable suppl chute I) throughwhich the slurry is fed to t e kiln, and at its other end with asuitable combustlon chamber. In such a kiln as this, which 1s rotatedslowly, more or less of the slurry, adhering to the inner Wall of thekiln, is carried upward with the wall of the kiln,

in the direction of rotation, and is continuously falling or slippingback toward the lowest part of the klln. The surface of the slurry whichis thus exposed to the hot products of combustion is not, however, verygreat as compared with the surface which would be exposed by the slurryflowing through a stationary cylinder. It is the object 0 this inventionto increase greatly the surface of slurry exposed to the hot products ofcombustion and therefore to'permit the rapid heating of the slurry andthe rapid driving'ofl of the contained water, as well as to cause thedust and the particles of unconsumed fuel carried by the hot products ofcombustion to be caught by the wet slurry and returned towardthe outletend of the kiln and at the same time cause the slurry to move inward,that is, toward the discharge end of the kiln. In accordance with thepresent invention it has been found that the desired result can be mosteffectively attained by placing within the kiln a series of chains 0which are helically arranged in the kiln. These chains are dipped intothe wet slurry at every revolution and considerable slurry adheres tothem and is carried upward and across the flowing stream of the hotproducts of combustion. Preferably the chains are slack, as represented,so that at any rate the greater part of the length of each chain, ateach revolution, is dipped into the slurry in the lowest part of thekiln and is made to traverse the entire cross sectional areaof the kiln.Many chains are used and whether they are arranged in a single helicalseries or grouped in different series, they constitute a series oflattices which compel the products of combustion to depart from astraight line of flow through the kiln and to be brought into contactwith the wet slurry which clings to the chains, whereby not only is theslurry quickly deprived of its water,

but the unconsumed particles of fuel and of dust which are carried alongby the products of combustion are caught and incorporated with theslurry, the dust particles remaining incorporated therewith, while theunconsuined particles of fuel are returned with the slurry to a pointwhere their combustion is completed. If the chains are slack, aspreferred, not only does the greater part of the length of each chainbecome coated with the wet slurry but, by reason of the continuousflexing of the chain, after it has become coated with the slurry, theslurry as it dries is broken away from the chain and falls into the wetslurry below. Again, if the chains are slack, as preferred, they willrest upon the innerwall of the kiln at its lowest part and will therebyprevent the incrustation of the slurry on the wall of the kiln.

The chains are connected to the inner wall of the kiln in any convenientmanner. As shown in Figs. 5 and 6, a T-headed bolt 03 may be employedfor the purpose, being adapted to engage the ends of two chain sectionsand to have the stem passoutwardly through the shell of the kiln to receive the nuts cl. In Fig. 3 two ends of each chain section are-shown asconnected to the drum about 120 apart, but it will be obvious that thedistance apart of the two oints at which the chain is connected to t edrum and the length of the chain between two points will be determinedby the conditions of operation. A

If the chains were disposed in planes at right angles to the axis of thekiln they would hinder rather than promote the inward or forwardmovement of the slurry naiaasi through the kiln. In order to promote theinward or forward movement of the slurry they must be arranged helicallyand with the inner end of each chain, that is, the end nearest thedischarge end of the kiln, circumferentially and in the direction ofrotation of the kiln in advance of the outer end.

I claim as my invention:

l. The combination with a rotary kiln for burning slurry, of crosschains secured to the interior of the kiln in planes oblique to the axisnear the feedin end of the kiln and adapted, in the rotation of thekiln, to be dipped into the Wet slurry, to become coated thereby, and tolift the slurry into the path of the hot products of combustion, each ofsuch cross chains being helically placed with its inner end in advance,circlnnferentially and in the direction of rotation, of the outer end.

2. The combination with a rotary kilnfor burning slurry, of slack crosschains secured to the interior of the kiln in planes oblique to the axisnear the feeding end of the kiln and adapted, in the rotation of thekiln, to be dipped into the wet slurry, to become coated thereby, and tolift the slurry into the path of the hot products of combustion, each ofsuch cross chains being helically placed with its inner end in advance,circulnferentially anal in the direct-ion of rotation, of the outer enThis specification signed this 24th day of May, A. D. 1918.

J OHAN S. FASTING. Witnesses:

MICHAEL AXEL RI UEsE, WILH. OLSEN.

